The present invention relates to an independent rear suspension system for an automotive vehicle, and more particularly to an independent rear suspension system which is so designed as to ensure stability and control of the automotive vehicle.
As shown in FIG. 1, a conventional independent suspension for a rear left wheel of a FF (Front Engine Front Drive) automotive vehicle comprises a strut 2 extending upwards from a rear left wheel 7, a radius rod 3 extending forward from the rear wheel 7, and a pair of parallel lateral links 4, 5 extending transversely inboards of the vehicle from the rear wheel 7. The strut 2 has an upper end pivotably mounted on the vehicle body and a lower end securely connected to a wheel support 8 having a spindle 9 for the rear wheel 7.
The conventional independent suspension as described above suffers from a drawback that each of the rear wheels is inclined toward a toe-out side when the rear wheel is subjected to a load F when the vehicle is being braked, and thus the vehicle loses control when making a turn under this condition.
This inclination of the rear wheels takes place owing to compliance steer of the suspension.
One known approach to solve the above mentioned problem is to steer the rear wheels in order to compensate for compliance steer phenomenon.
Japanese Utility Model Application Provisional Publication No. 55-147968 discloses a rear wheel steering arrangement designed to compensate for the compliance steer. FIG. 2 illustrates in diagram a portion of this known arrangement. Referring to FIG. 2, rear wheels 10 are supported on axle shafts integral with left and right knuckle arms 14d, 14b which are mounted by king pins 14e, 14f to a suspension beam 14a. The knuckle arms 14d, 14b are interconnected by a tie rod 14c as shown. A servo cylinder 20 has a piston rod 20c operatively connected to the knuckle arm 14d. The servo cylinder 20 has two chambers 20a, 20b which are connected to a control valve (not shown). The control valve is operative responsive to lateral acceleration and selectively pressurizes the chambers 20a, 20b so as to steer the rear wheels 10 in the same direction as the front wheels (not shown) are steered.
This known steering arrangement is found to be effective in compensating for the compliance steer. However, since it requires king pins in mounting the wheels in a similar manner to the front wheels, this arrangement can not be embodied in an independent rear suspension of the type as shown in FIG. 1.